Synelmis gibbsi, Salazar-Vallejo, 2003

Salazar-Vallejo, Sergio I., 2003, Revision of Synelmis Chamberlin, 1919 (Annelida, Polychaeta, Pilargidae), Zoosystema 25 (1), pp. 17-42 : 26-28

Synelmis gibbsi n. sp.

( Figs 1C ; 5 )

Synelmis albini – Gallardo 1968: 61, 62, pl. 12, figs 2-4. — Gibbs 1971: 137 (partim). —? Amoureux 1983: 368. — Rosenfeldt 1989: 221.

Ancistrosyllis rigida – Hartman 1954: 625 (Enirik Island only). —? Rullier 1963: 181. — Reish 1968: 213 (partim).

TYPE MATERIAL. — Syntypes: Komimbo Bay , NW Guadalcanal Island, Solomon Islands, 20.VII.1965, P. E. Gibbs, 2 syntypes ( BMNH 1970.308 ) ; Enirik Island , Bikini Atoll, Marshall Islands, intertidal, 1946, 1 syntype, anterior fragment ( LACM-AHF 2093 ) .

TYPE LOCALITY. — Solomon and Marshall islands.

ETYMOLOGY. — Named after Dr Peter E. Gibbs, for his contributions to the study of polychaetes in general and especially for his work as part of the Royal Society Expedition to the Solomon Islands, which collected part of the specimens upon which this description has been based.

OTHER MATERIAL EXAMINED. — Indian Ocean. Red Sea, Sonné Expedition, stn 40GKH, 21°13.50’N, 37°39.60’E, 831 m, 18.X.1977, 1 specimen in three pieces (SMF 3805). — Persian Gulf, island off Kuwait, sandy pockets in intertidal rocks, M.-B. M. Mohammad, 1 specimen (BMNH-1971.65). — India, Bay of Bengal, off Honarak (Black Pagoda), Orissa, 2 specimens (MNHN A436).

Western Pacific. Bay of Nha Trang , Naga Expedition, Mao Tien, stn 138I, small bay NW of Mui Dang Ba, 3 m, coarse shell and coral debris, 1 specimen in two pieces ( LACM-AHF 11678 ) ; stn 296, northwest of Mui Dang Ba , 4 m, fine and calcareous sand, Vietnam, some fragments ( LACM-AHF 11679 ). — W of Tab Island, Papua New Guinea, 10 m, 1.I.1995, F. Pleijel, 1 specimen (ECOSUR-PILA-3) .

DISTRIBUTION. — Red Sea, Persian Gulf, India, Solomon Islands, Vietnam and Papua New Guinea, in shallow water. The record by Rullier (1963) for the Marmara Sea was on a specimen with 55 setigers and 3 mm long but his record lacks any additional information and requires confirmation. The record by Amoureux (1983), from the Gulf of Aquaba, in coral, is questionably assigned to this species.

DESCRIPTION

Body subcylindrical, pale, largest specimen 52 mm in lenth, 0.7 mm in width, 167 setigers. Body with dark pigmented glands on lateral sides of setigers 1-2, glands smaller, less pigmented in setigers 3-5.

Prostomium rectangular, longer than wide, with biarticulated palps, well separated from each other, palpostyles small rounded, ventrolateral papillae long. Three antennae about same width, lateral antennae located anteriorly, as long as palps; median antenna longer, placed posteriorly ( Fig. 5A ). One pair of big dark eyes, sometimes duplicated and appearing fused.

Parapodia with subequal cirriform cirri, slightly swollen basally from setiger 20. Dorsal cirrus of setiger 1 longer ( Fig. 5B ) than following ones ( Fig. 5C ). Median setigers with parapodial cirri swollen basally ( Fig. 5D ) but posterior ones become cirriform ( Fig. 5E ). Pygidium with dorsal anus ( Fig. 5F ); two long cylindrical anal cirri, can be as long as the last 3-4 segments.

Notosetae only notospines, starting from setiger 5; neurosetae mostly broken but three kinds are seen: abundant capillaries and limbate setae and one furcate setae with apparently symmetrical tips ( Fig. 1C ). Everted pharynx up to 0.8 mm in length, length is equivalent to first four setigers; pharynx tip and surface smooth. Posterior pharynx up to 12 setigers in length, followed by rather convoluted stomach as long as 20 setigers.

Comments on other materials

Specimen from the Red Sea, is a complete juvenile torn into three pieces. Together they are only 13 mm in length and 0.2 mm in width, with 49 setigers and two preanal asetigers. There are no eyes. Notospines start at setiger 5. Posterior brain lobes are apparently detached. The anterior gut could not be seen.

Specimen from Kuwait is damaged but the diagnostic features are noticeable. It had apparently been compressed and its median antennae is very wide and thin. Body subcylindrical, tapering towards both ends; complete but almost torn in two around setiger 10 and about the first third of the body. It is 53 mm long, 0.8 mm wide, with 162 setigers.

Specimens from India partly dehydrated; they are anterior fragments, one with everted pharynx is 26 mm in length, 0.8 mm in width and has 97 setigers; the second is 42 mm long, 0.8 mm wide with 149 setigers; the third one is 33 mm long, 0.6 mm wide with 125 setigers. Segments appear multiannulated due to previous dehydratation; eyes are difficult to be detected but glands can clearly be seen before and after each parapodia in median segments.

Specimens from Vietnam are in poor condition. One anterior and one median fragment that might fit are soft, pale. They are about 48 mm in lenght and 0.3-0.5 mm in width (the difference is because the median fragment is flattened). Setigers total 120. The everted pharynx is 1 mm in length and it should be equivalent to 10 setigers. The other materials dried, consisting of a posterior fragment including the pygidium and a median fragment that might fit. They had

32 and 21 setigers respectively.

Specimen from Papua New Guinea is a juvenile;

it is pale, twisted with its pharynx slightly everted.

It is 16 mm in length, 0.5 mm in width with about 80 setigers. It has two eyes. There is a slight coloration in the glands in setigers 1-2. The anterior fragment from the Marshall Islands is 30 mm

in length, 1.0 mm in width and has about 94setigers. It has two eyes but there is no clear pigmentation in its anterior glands.

REMARKS

Synelmis gibbsi n. sp. is closely allied to S. amoureuxi n. sp. from the western Atlantic Ocean, and S. knoxi from New Zealand, but they differ in that the former has a longer median antenna and a longer dorsal cirrus in setiger 1.

Figures

FIG. 1. — Furcate setae from different Synelmis species; A, S. britayevi n. sp. (LACM-AHF-2092); B, S. emiliae n. sp. (UANL-318); C, S. gibbsi n. sp. (BMNH-1971.65); D, E, S. gorgonensis (Monro, 1933) n. comb.; D, BMNH-1932.12.24.128; E, ZMH-14211; F, S. harrisae n. sp. (LACM-AHF-2095); G, S. rigida (Fauvel,1919) n. comb.(BMNH 1970.310); H, S. rigida n. comb. (MNHN A71); I, J, S. sotoi n. sp. (MNHN A888 As296). Scale bar: 30 µm.

FIG. 5. — Synelmis gibbsi n. sp. from the Solomon Islands (BMNH 1970.318); A, anterior end in lateral view; B, setiger 1 in posterior view; C, setiger 10 in posterior view; D, setiger 20 in posterior view; E, setiger 50 in posterior view; F, posterior end in lateral view. Scale bars: A, F, 0.2 mm, B-E, 100 µm.